Multi-head rod and bar bender



Jan. 10, 1961 R. J. PETROFF 2,967,561

MULTI-HEAD ROD AND BAR BENDER Filed 001:. 24, 1957 4 Sheets-Sheet 1 #05 92 /93 Er .2 BEND c 0 BEND K 8 it? 25310212 0 eesroee 32% i I 3 2 RE 1 89 6 2 I y l 122 RESEIZVE.

it Q 0 120 5 121 INVENTOR.

in a 20255.62" JPLTKOFF Jan. 10, 1961 PETROFF 2,967,561

MULTI-HEAD ROD AND BAR BENDER Filed Oct. 24, 1957 4 Sheets-Sheet 2 L- 5 K. i 47 4? ,EZ A L INVENTOR.

E0552?" JPCTZOFF Jan. 10, 1961 R. J. PETROFF MULTI-HEAD ROD AND BAR BENDER 4 Sheets-Sheet 5 Filed 001;. 24, 1957 N nhw IN VEN TOR. @5527 J PE T 10, 1961 R. J. PETROFF 2,967,561

MULTI-HEAD ROD AND BAR BENDER Filed Oct. 24, 1957 4 Sheets-Sheet 4 IN VEN TOR. 05587 ZP70FF United States Patent MULTI-HEAD ROD AND BAR BENDER Robert J. Petrotf, Broadview, Ill., assignor to Pines Engineering Co., Inc., Aurora, lll., a corporation of Illi- This invention relates to multiple-head bending apparatus and concerns itself more particularly with equipment of this class which utilizes motive power for the simultaneous execution of several bending operations.

Rod and bar stock is bent into substantially rectangular shapes for various purposes among which is well known several styles of reinforcing stirrups. Hot rolled surfaceribbed steel stock is used in making these articles which stock may vary in thickness from about one-half to one inch. This material is usually supplied by steel mills in large rolls of indefinite length and hence'requires to be straightened and cut ofi" into suitable lengths before introduction into bending machines.

It is recognized that various customers of such articles do require somewhat different shapes in reinforcing stirrups, as regards dimensions of the sides, terminal loop or hook formations, etc., so that the supplier of this class of goods must be prepared to bend the stock with considerable variation, as will later be more specifically described.

The supply stock from which such articles are made is characteristically crusted with rust that during bending becomes freed into a powdery offal that is deposited over exposed parts of the machine and ultimately may enter vital and critical moving or journal components to effect rapid wear and destruction. In order to avoid or reduce such deleterious elfects to minimum, bending machines of this class should be designed with protective features and least exposure to working parts.

Accordingly, a primary object of the present invention is to provide a universal bar bender which may be tooled, set up and adjusted to a wide range of dimensional variations as well as full reversibility of bend arbor rotation.

Another object of the invention is to provide such a machine with maximum shrouding and other features of protection whereby to be least susceptible to contamination and wearing of parts on account of the high yield of abrasive offal from the bar stock worked on.

Another object of the present invention is to provide a bar stock. bending machine which includes a system of tools and fixtures which produces a simulated rolling action with inert parts whereby to effect small frictional losses while engaging bar stock with surface ridges.

Yet another object of the invention is to produce a multiple-head bending machine which may be hydraulically actuated while also being precisely adjustable and controllable for low skill manipulation.

For further and more explicit disclosure of the foregoing and other objects and purposes of the invention, attention is now directed to the following detailed description of an exemplary structure illustrated in the accompanying drawings, in both of which like reference numerals designate corresponding parts throughout, and in which:

Fig. 1 is a perspective view of a multiple-head bending machine with portions broken away for the sake of compactness, and which embodies various features of the present invention;

2,967,561 Patented Jan. 10, 1961 Fig. 2 is a diagrammatic circuit illustration of the hydraulic control and operating system with parts represented symbolically;

Fig. 3 is a diagrammatic circuit detail illustration of a stroke limiting control valve and direction reversing apparatus as utilized in the present invention;

Fig. 4 is a front elevational view of one of the multiple heads which constitutes a unit of the present invention;

Fig. 5 is a transverse sectional view taken along line 5-5 of Fig. 4;

Fig. 6 IS a cross-sectional detail view taken approximately along line 6-6 of Fig. 5;

Fig. 7 is a cross-sectional detail view taken approximately along line 7-7 of Fig. 5;

Fig. 8 is a grouped view of several typical reinforcing bar stirrups, and

Figs. 9 to 12 are enlarged scale progressive operational detail views of the forming tool and fixture components constructed in accordance with the present invention.

Referring more particularly now to Figs. 1 5 and 6, attention is directed to reference numeral 21 which denotes generally a base structure having a topmost bedrail section carried on a slab or table member 22. The latter should have sufficient length to correspond with the longest stock lengths to be processed. On the top surface of the slab 22, or elsewhere paralleling the ways or bedrails, there may be situated a rack bar 23 with whose teeth there is adapted to mesh those of an adjustment pinion 24, Fig. 7, carried by a shaft 25. The latter extends the width of base casting 26, Fig. 5, so that by applying a removable crank wrench 27 to the squared headv 28 thereof and turning same one way or the other, each one of the several heads 31, 32, 33 and 34, Fig. 1, maybe nicely located along the length of the bedrails. of table 22, which member may be provided with graduations to provide a guide index thereby.

After being thus located, each head31 to 34 may then be clamped securely at such station by means of lugs 35 which are able to be screw tightened to grip the edge of slab 22 on both sides of the table. The base casting or forging 26 may be an integral unit with the driving stock portion 36, Fig. 5, and both of these members may be provided with cylindrical bores. The base casting bore is lined with sleeve bearings 37 and 38 fore and aft for rotatably supporting a power driven sleeve. 39, Figs. 6 and 7. The driving stock casting 36 is turned at. the extremities of its bore to receive the bearing races 41 and 42 which support for rotation a power driving sleeve 43.

A multiple chain drive 46 is trained around sleeves 43 and 37, meshing with a corresponding series of tooth sprockets 44 and 45, Fig. 7, formed in the central portions thereof. When rotary power which may be hydraulically generated in the single vane type hydraulic motors 47, is imparted to the sleeves 43, Fig. 5, similar rotary motion at somewhat reduced rates of speed is transmitted to sleeves 37 by means of the chain drives 46. Conventionally, such motors are limited in extent of rotation to about 270 degrees so that the working sleeves 37 after undergoing a one to two sprocket ratio of reduction may yet describe about degrees of rotation. bends this amount of angular rotation is sufficient nevertheless to execute the type of bends most frequently required. However, by means of the unique design of bending dies and fixtures here disclosed, it ismade possible for 135 degrees of rotary motion to produce as much as degrees of bend in the bar stock, as will be explained.

At the forward end of driving sleeves43 there are drive fit mounted radial tooth clutch portions 49 which mesh with spring loaded driven clutch portions 51, which latter elements may also include cam discs 52, Fig. 5, whose lobes are adjustable angularly by the expedient of For most manipulation knobs 53. By pulling any of the knobs 53 forward against its spring tension and then rotating it to a selective position while the clutch elements are apart, a set up operator may relocate the cam lobe 52 angularly to operate a valve arm 120 whereby to arrest hydraulic motion at a precise degree of rotation.

Driven sleeve 37 contains an inner sleeve 54, Figs. and 7, journalled in bearings 55 for longitudinal motion only and keyed as at 56, Fig. 5, to prevent rotary motion thereof. A seal ring 57 at the forward end of sleeve 54 serves to exclude contaminants from entering the journal region. Inner sleeve 54 has a reduced diameter bore at its front end adapted to receive in tight fitting relation the stud portion 58 of a non-rotatable fixture or core section which includes a circular disc 59, a bend radius pin 61 that juts perpendicularly from one half area portion of the disc 59, and a hold-down segment 62 which juts perpendicularly from the other one half area of the disc 59 together with a chordal plane surface facing said radius pin 61, Figs. 9 to 12.

The space between the two described jutting members 61 and 62 should correspond to the thickness of the stock to be bent. Beyond the stud portion 58, internally of sleeve 54, the bore is preferably larger and thereat houses an anchor plug 63 having a forward internal annular recess 64 which may receive the toe 65, Fig. 6, of a clamp nut which may be drawn tight with a bolt 66 that extends through the disc 59, integrating stud 58 with plug 63.

A compressible coil spring 67 urges with one of its ends against a shoulder of anchor plug 63 and with its other end against the internal surface 68, Fig. 5, of a dome shaped case housing 69. A shaft 71 is threaded or otherwise secured to anchor plug 64 at its forward end,

after passing through the wall 72' of case housing 69, is secured by athreaded nut to a hydraulic piston assembly 73, reciprocally movable in a cylindrical housing projection 74 at the rear of dome 69. Accordingly, spring 67 tends to maintain the anchor plug 63 together with the attached non-rotatable fixture elements 62 and 61 in the active position, shown in Fig. 5, but when hydraulic pressure is introduced through inlet pipe 75, piston 73 spring 67 will restore the several elements to their normal condition, as shown in Fig. 5. When a bending operation is such that following its execution the bending tools ,thereof are required to be withdrawn from the planar alignment with the bar stock, the hydraulic fluid supply pipe 75 thereof may be connected into the return stroke side of its bend operating motor 47. This will allow the fixtures 61 and 62 of such unit to be withdrawn as an incident of the motor return stroke and not require separate pipe lines and valving for this purpose.

As best shown in Figs. 1, all of the non-rotatable tool elements 61 and 62 of the several heads 31 to 34 may, for forming a set of bends as required to make a stirrup such as that indicated 78, Fig. 8, be arranged as shown in Fig. 1, with the radius pins 61 down and the holddown segments 62 up. The rotatable tools 77 and 78, on the other hand, may assume diiferent positions as the nature of the bend operations require. More specifically, the pressure shoe 77 of head'31 may, for forming style 78' assume a normal or starting position approximately at ten oclock, as viewed frontally, while that of head 34, its jointly operated mate, assumes one symmetrically opposite or at two oclock.

Since the described heads 31 and 34 performterminal bends, needing about 150 degrees of bend performance, their hydraulic motors 47 will have to undergo almost total rotation. Accordingly, the shoes 77 of these heads will end up at about the six oclock position, each traveling about 110 degrees of rotation, as best understandable 'cut to lengths.

4 from Figs. 9 to 12. When these bends have been completed, the shoe 77 will be returned to starting position and, at the same time that the return is made, the retraction pistons 73 thereof will make their non-rotatable tools 61 and 62 recede. Heads 33 and 32 may then execute their inside bends whereupon the ends of the stock will be free to respond. In like manner all forms of four and five station bends are capable of being executed with as many heads placed in alignment, by arranging their sequence of operation and non-rotatable tool recession from outermost ones inward.

Most often, the normal or starting position of inter mediate head bending tools 77 is not critical because any idle approach movement will merely take a fraction of time longer to execute. The positioning of the bending tool base plates or surrounding sections 78 is an adjustment that may be accomplished coarsely, as provided for by the carried locating pins or studs 79 and 81, Figs. 4 and 5. These are circumferentially spaced apart an angular distance from each other which corresponds to a multiple of the distances between the arcuate notches 82 in flange 83. The locating studs 79 and 81 function also as securing means, being each provided with cut-away segments or notches 84 which are deep enough to clear the projecting portions between adjacent arcuate notches 82 and upon manipulation by means of their lever arms 85, to then nest clampingly within chosen notches 84.

During a typical bending operation, such as that progressively illustrated by the views in Figs. 9 to 12, the bending shoe 77 first engages the bar stock at a point 131 remote from the radius pin 61, Fig. 9, due to the plotted special curvature which has been designed into the symmetrical pressure shoe 77. As the action of the rotatable surrounding section proceeds, however, the point of tangency moves inwardly and toward the radius pin 61, after the manner represented by the succeeding point of tangency arrows 132, 133 and 134. As a consequence of this unique performance, not only does the shoe produce a simulated rolling action as it passes over the rough or ribbed surface of the stock 135, but more important, it efiects a bending acceleration in terms of results impressed upon the work measured by the angular movement of the tool 78.

The extent of this acceleration is an impressive one, indeed as is evident from the four figures being discussed. While the tool is undergoing a total angular travel of about degrees, the bar stock is being bent at least degrees. An eye inspection of the relative motion described by the bending die 77 and that described by the stock sample during the course of progress represented 'in the diagrammatic figures is sufiicient to verify the phenomenon of bend stroke acceleration. The absence of rollers and other forms of wearable journaled parts in the proximity of the bending operations makes for longer lasting, attention-free tool implementation, a consideration which is especially important to production and cost factors.

When a bending machine has been appropriately tooled and set up for production by the shop foreman or supervisor, rod stock supplied in rolls of indefinite length requires first to be passed through a straightener and then This is usually done with conventional machinery located near the bending machine stations so that the rod lengths may then be introduced, singly or in workable multiples into the space alignment between the several non-rotatable die elements 61 and 62. When this loading has been made, the operator of the presently described machine has but to move a valve control handle 88, Fig. 2, upwardly from its neutral position to that marked bend, and the following will result.

Fluid under constant pump operated pressure from a pump symbolized 89 will be allowed to flow over line 91, thence through the reversible valve 92, conduits 93, 94 and 95 to the bend actuating side of hydraulic motors taneously and in opposite directions each making its terininal loop bend at its respective end of the piece part rods. Should one of the motors complete its course ahead of the other one, a contingency that may well result in hydraulic systems, the present control system provides for the continued supplying of power, nonetheless to the late responding motor until the latter has had the needed time to complete its function. The means whereby this is accomplished will be explained in connection with the detailed description of Fig. 3, to follow later.

Meanwhile, it will be noted that the extreme heads 31 and 34 have been operated in response to the bend regulation of handle 88, and that these units now need to be brought back to their normal condition. This is done by shifting the handle 88 to its restore position, and as a result pressure and return sources will be reversed with relation to the conduits which lead to the motors 47 of units 31 and 34. As a consequence of pressure entering lines 99 and 103, hydraulic motors 47 of heads 31 and 34 will at once begin to rotate in directions opposite to that described during their bend phase and at the same time pressure will also be directed into the respective retraction cylinders 74 thereof causing the non-rotatable tool elements 61 and 62 of these units to be drawn out of effective position. This side effect is the result of providing lines 101 and 104 connected directly with the return circuits 98 and 102.

The operator may then move handle 105 to its bend position and as a consequence pressure fluid will enter the motors of heads 32 and 33 causing them to rotate their rotatable surrounding plates 78 in the directions prearranged for making the interior bends at points 137 ;:and 138, Fig. 8, of stirrup type 78'. .quire that the extremities of the bar stock lengths be free These bends re- .to move, one clockwise and the other counterclockwise downwardly, which clearance is now afforded by reason .of the retraction of the tools 61 and 62 of heads 31 and 134, as well as by reason of the restoration of shoes 77 associated with these heads.

The just described secondary bend operations are made .by obvious hydraulic power and control circuits similar :to the ones traced in connection with the primary bendiing motors of heads 31 and 34, and then these are similarly restored by depression of the handles 105 to restore position. When as a result of the restore operation, the retraction cylinders 74 of heads become effective, the tools 61 and 62 thereof will recede and the completely formed piece parts will be permitted to gravitate into suitable collection receptacles or conveyor means provided for this purpose.

The disclosure in Fig. 2 is essentially a simplification for the sake of general description and does not concern itself with specific circuit problems. In Fig. 3, however, certain of the functional control features are more detailedly dealt with, as will now be explained. A four-way control valve 111 is preferably located beyond the junction of return lines 102 and 104, so as to enable line 102 to be connected to inlet line 103 or line 117, ion the one hand while return line 116 leading out of spool valve 112 is at the same time connectable with inlet 117 or inlet 103, alternatively. This enables motor .47 to be optionally right or left handed for execution of the bend movement, as where a stirrup form such as that indicated 141 or 142 is to be made.

With valve 111 disposed as shown in solid outline in Fig. 3, operating fluid over line 95 is traceable to paths 113 and 114. Of these, path 113 is open through spool valve 112 at this time and hence further traceable over j line 115, line 116, through the four-way valve, now disposed to extend the described line to inlet 117 which will move the hydraulic motor 47 clockwise. When the during which to arrest movement, encounter is made with a valve operating lever 120 which results in' a shifting rightward of the spool in valve 112. This blocks the continuation path for line 113 and opens a path for line 114. The blocking of path stops further flow to the motor 47, but does not prevent such flow to any other motors 47 Whose supply is over the same main supply line 95 and whose stroke may not have yet reached completion. With completion of all motors 47, the operator will move hand lever 88 to restore, whereby a reversal of pressure for return will be made and line 95 becomes the return side while line 102 becomes the new pressure side.

As a consequence of operating pressure coming over line 102, fluid will enter inlet line 103 and motors 47 will start their movement opposite to their bend stroke or in the illustrated case, counterclockwise. Immediately, cam lobe 118 rides out from beneath lever 120 and the spool of valve will by its spring be restored to normal, as shown in the drawing. This action bars line 114 again and reopens line 113. As a result the exhausting of fluid from motor 47 which momentarily was permitted to travel out over lines 117, 116, one-way valve 121, lines 122, 114 to 95, will now continue instead over lines 117, valve 111, lines 116, 115, 113 to line 95. When the parts have all been brought back to starting condition, motors 47 will be arrested by their own motion limiting blocks and the operator may then shift handle 88 to neutral position, as shown.

While the present disclosure has been made in contemplation of specific structural embodiments, it is not intended thereby to limit or restrict the scope of the invention, but instead to be permitted a latitude of interpretation as defined by the hereunto appended claims.

I claim:

l. A multiple head bar bender which comprises, a series of machine heads horizontally adjustable in an alignment, a work spindle assembly in each of said heads comprising a longitudinally shiftable core portion and a rotatable sleeve portion encircling said core portion, tool elements carried by said core portion including a bending radius pin and a hold-down segment, an additional tool element carried by said rotatable sleeve portion including a circumferentially adjustable disc and a pressure shoe extending perpendicularly from said disc, means to secure the disc circumferentially adjusted relative to the sleeve portion, said pressure shoe and said disc being rotatable with said sleeve portion about a radius eccentric with respect to said radius pin and said pressure shoe having an I interiorly facing symmetrically duplicated surface curvature of substantially involute contour whereby to present progressively a sequence of core approaching tangents to a length of stock supported between said radius pin and hold-down segment whilst bending same about said radius pin.

2. A system of bending fixtures which comprises, an interior non-rotatable portion which includes a circular plate, a bending radius pin perpendicular to and secured in said circular plate within one-half of its total circular area, and a hold-down segment spaced from said bending radius pin and secured to said plate within ari area diametrically opposed to said pin, an exterior portion which includes a disc having a circular axial aperture for receiving therewithin said interior portion circular plate and a pressure shoe perpendicular to and integral with said exterior portion disc, said shoe having an interiorly facing wall surface of oppositely symmetrical generally involute curvatures, each of said curvatures comprising a generation of successive points of tangency from an outermost extremity inwardly as said shoe engages a length of bar stock disposed within the space between said radius pin and said hold-down segment of said interior portion fixture.

3. A bending head for use in multiples which comprises, a base structure adapted to be secured upon a horizontal bed, means for securing said structure to said bed in different horizontal stations, a cylindrical core section longitudinally shiftable between active and withdrawn positions in said base structure, a sleeve section encirclingrsaid core section and rotatable thereabout, a work holding die carried by said core section, a work bending die carried by said sleeve section, hydraulic means for shifting said core section between active and withdrawn positions, hydraulic means for rotating said sleeve section about said core section, and adjustable cam operated means for arresting said sleeve section hydraulic rotating means at predetermined points of rotation.

4. A power operated bending head adapted for use in multiples which comprises, a principal housing having a lowermost work performing axis and parallel thereto an uppermost power transmission axis, said work performing axis including a longitudinally shiftable core portion and surrounding it a rotatable power driven sleeve portion, said core portion including atone of its ends a stationary die having a bending radius element and a hold-down element, said elements being spaced from each other to receive therebetween lengths of a bar stock material to be bent into predetermined shapes, said sleeve portion including at its corresponding end a wiping die having a substantially involute curvature surface facing said core portion, said power transmission axis comprising a cylinder bearing peripherally thereof, sprocket elements adapted to mesh with a belt for driving said work performing sleeve portion, hydraulic means for rotating said power transmission cylinder, circumferentially adjustable cam means rotatable with said power transmission cylinder,and'a'device operable by said cam means for arresting the flow of hydraulic fluid to said hydraulic means for thereby controlling the degree of angular rotation im- -parted to said transmission and work performing axis sleevel portion.

5. In a multiple head bar bending machine, a series of bending heads each' comprising a holding fixture portion, 'a bending'fixture-portion, a hydraulic motor for shifting said holding fixture portion between operative and retractile positions, a hydraulic motor for rotating said bending fixture portion in alternative directions, cam means circumferentially adjustable in relation to and movable by the rotation of said bending fixture portion, and a-hydraulic fluid power circuit including a supply line' for fluid under "pressure, a fluid return line, a plurality of tributary lines leading to said hydraulic shifting and rotating motors, valve means for reversing said supply and return lines in relation to said tributary lines to thereby'effect reversal of their bend and restore move ments, and additional valve means associated with each 8 of said bending fixture portions and operable by said cam means for arresting the passage of power fluid to its related motor when its bending fixture portion has completed a predetermined degree of rotation.

6. The combination set forth in claim 5 in which sai additional valve means comprises a slide member contained in a housing, said slide member having a load spring for maintaining it in normal position and a cam means for holding it in a shunt position, said normal position establishing a path over said tributary lines for said fluid power to reach said bending fixture hydraulic motor and said shunt position establishing a path for diverting said fluid power path during the return stroke to dissipate the operating fluid thereof while said cam means is arresting the fiow over said tributary lines.

7. A multiple head bar bender which comprises, a series of machine heads horizontally adjustable in an alignment, a work spindle assembly in each of said heads comprising a longitudinally shiftable core portion and a rotatable sleeve portion encircling said core portion, tool elements carried by said core portion including a bending radius pin and ahold-down segment, additional tool elements carried'by said rotatable sleeve portion including a circumferentially adjustable disc and a pressure shoe extending perpendicularly from said disc, a pair of circumferentially spaced locating studs on said circumferentially adjustable disc, a flange on said rotatable sleeve portion having a series of spaced notches into spaced pairs of which said locating studs are adapted to be selectively seated, said pressure shoe and said disc being rotatable with said sleeve portion about a radius eccentric with respect to said radius pin and said pressure shoe having an interiorly facing symmetrically duplicated surface curvature of substantially involute contour whereby to present progressively a sequence of core approaching tangents to a length of stock supported between said radius pin and hold-down segment whilst bending same about said radius pin. 

